Chinese researcher pushes US ahead in race to build ultra-precise nuclear clock
Graduate student Zhang Chuankun helps lab pinpoint laser frequency to drive timekeepers that could test foundations of physics
A graduate student from eastern China is at the centre of a major advancement in precision timekeeping, ending a decades-long search for an essential piece of the puzzle of building a nuclear clock.
Ye, a pioneer in ultra-precise timekeeping credited with building the world’s most accurate atomic clock, said Zhang was among “the very best” students he has worked with.
Zhang, a native of Shandong province, was instrumental in developing a special laser device known as a vacuum ultraviolet (VUV) frequency comb at Ye’s lab at JILA, a joint institute of NIST and CU Boulder.
“An optical frequency comb acts like a ruler for light,” Zhang said. “It allows for extremely accurate frequency measurements by comparing unknown frequencies to a known standard.”
His work enabled Ye’s lab, which began developing the comb in 2005, to pinpoint the precise laser frequency needed to trigger a nuclear transition and drive a nuclear clock.